A plan is outlined to develop an inexpensive method for the evaluation of self-administered drug reinforcers in rats. A direct comparison is planned between the proposed method and the more standardized technique currently used by the majority of investigators in self-administration research. Each method will be cross-checked against the other to determine their relative reliabilities with respect to the interpretive value of each in analyzing drugs with potential reinforcing capacities. Experiments to study the effects of schedules of reinforcement, drug interactions, and dose size are presented.